1. Field Of The Invention
The present invention relates to a cylinder head for an internal combustion engine. In particular, the cylinder head of the present invention has one valve per cylinder for both the intake and exhaust functions of either a two-cycle or a four-cycle engine. More particularly, the cylinder head of the present invention employs a poppet valve in communication with the combustion chamber and is designed to exceed the air flow capability (outflow) of conventional two, three, and four valve per cylinder. Because the power of an engine is proportional to the air flow capacity, the cylinder head of the present invention yields an increase in power over conventional cylinder heads.
The present invention also discloses a process of operating the cylinder head in conjunction with an internal engine.
2. Prior Art
Fuel efficiency requirements by the United States and other governments throughout the world become increasingly more difficult to attain. Fuel efficiency dictates lighter weight cars and smaller engines compared with engines produced as little as ten years ago. To obtain increased power from the smaller engines, manufacturers are abandoning typical two-valve per cylinder engines (an exhaust valve and an intake valve) and instead manufacturing engines having multivalves, such as two intake valves and one exhaust valve, or two intake valves and two exhaust valves. Such multivalve engines are designed to increase the flow of the fuel air mixture into the combustion chamber to achieve the increased power from each cylinder of the engine.
Various problems arise, however, in the use of multivalve engines. First, design considerations become much harder to achieve because two intake valves and two exhaust valves must now be designed and operated in a space (the top of the combustion chamber) which traditionally only held one intake valve and one exhaust valve. Moreover, controlling each of these valves in synchronization, or independently, requires several times more moveable components, thereby increasing manufacturing cost and potential maintenance and repair costs.
Second, cramming multivalves into a combustion chamber decreases the efficiency of each valve because the size of each valve is reduced and the effective curtain area (the area of air flow around each valve) is reduced because flow from one valve interferes with the flow from another valve, and because space limitations require that the valves be positioned close to the combustion chamber side walls, thus further reducing the effective curtain area of the valves.
Third, multivalve engines are not clean, compared with two-valves r cylinder engines, and therefore carry an emissions debit such as higher hydrocarbons, carbon monoxides, and oxides of nitrogen. It has been reported that the emissions debit of multivalve engines, depending on the size of the engines, is anywhere from 25 to 40 percent higher in hydrocarbons. Thus, increasing the flow to achieve more power by employing multivalve engines provides a whole host of other problems which must be overcome while simultaneously meeting increased fuel efficiency requirements.
One potential solution to this problem is to employ a rotary valve positioned atop the combustion chamber, which at one point of the rotation of the valve, the intake of a fuel air mixture into the combustion chamber occurs, while at another location of the rotary valve, the exhaust gases are permitted to exit the combustion chamber. A single rotary valve per cylinder design has been known for many years and suffers many problems which to this day have not been overcome. Chiefly among those problems is the inability to adequately seal around the rotary valve to prevent oil leakage, fuel air mixture leakage, and exhaust gases leakage.
Another solution is proposed by U.S. Pat. No. 3,097,633 to Klein. This patent employs a single poppet valve in the cylinder chamber and a curved deflector gate to oscillate between an intake conduit and an exhaust conduit. It is believed that this combustion head design suffers several defects making the design impractical for today's internal combustion engine requirements. First, there is an increase in emissions due to fuel trapped under the curved deflector gate as it oscillates between the open and closed positions where unburned hydrocarbons are exhausted from the combustion chamber. Secondly, it is believed that a pulsating motion which negatively affects flow efficiency is set up in the intake conduit, particularly at high speeds, because the curved deflector gate opens into, and therefore counter-directional to, the flow of the fuel air mixture. Thirdly, during the exhaust cycle, the rush of exhaust gases tends to deflect the curved deflector toward the intake position, thereby tending to force exhaust gases into the intake passage. Fourthly, the bight side of the curved deflector is exposed to both the fuel mixture and the exhaust gases. Any carbon deposits on the bight side could cause undesirable pre-ignition and/or dieseling by virtue of the fuel/air mixture contacting the hot carbon deposits. Fifthly, as the engine heats up, the deflector gate, which is in contact with the exhaust gases, also heats up. The expansion of the deflector gate enlarges the slot, and sealing becomes difficult to achieve which may permit the escape of unburned hydrocarbons.
There continues to be a need for an improved cylinder head design to possess flow characteristics equal to or exceeding that of multivalve engines, while simultaneously improving the emissions debit. The present invention, it is believed, meets not only these criteria, but also possesses other characteristics manufacturers of internal combustion engines desire.